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D. KELLY'Sv-W. H. HOFFMAN.

STEAM GENERATOR.

Patented 001;. 25,1881.-

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2 Sheets-Sheet 2. D. KELLY 8u W. E. HOFFMAN.

(No Model.)

STEAM GENERATOR.

No. 248,759. Patented Got. 25,1881.

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DANIEL KELLY, OF PHILADELPHIA, PENNSYLVANIA, AND JVILLIAMA H. HOFFMAN,OF PASSAIO, NEW JERSEY, ASSIGNORS OF ONE-THIRD TO XVALIER K. LUDWIG, OFPHILADELPHIA, PENNSYLVANIA.

STEAM-GEN ERATO R.

SPECIFICATION forming partef Letters Patent No. 248,759, dated October25, 1881.

Application filed June 2S, 1881. (No model.)

To all whom it may concern:

Be it known that we, DANIEL KELLY, of the city and county ofPhiladelphia, in the State of Pennsylvania, an d WILLIAM H. HOFF- MAN,of Passaic, in the county otPassaic and State of New Jersey, haveinvented a certain new and useful Improvementin Steam-Generators,ofwhichthe following is a specication.

Our invention consists in the combination, with the furnace andcombustion-chamber ot' a steanrgenerator, of air-chambersin the front ofthe furnace and in the bridge-wall, and a novel arrangement of ues,whereby air is heated by the waste products of combustion escaping fromthe generator and introduced into said air-chambers, from whence itpasses into the furnace and combustion-chamber.

In the accompanyingdrawings, Figurel represents a longitudinal verticalsection of a steam-generator embodying our invention. Fig.2 represents aplan thereof. Fig. 3 represents a transverse vertical section thereofupon the dotted line a: x, Fig. l; and Fig. el. represents 'a modifiedform ot' generator, also enibotlying our invention.

Similar letters of reference designate corresponding parts in all thefigures.

Referring., iirst, to Figs. 1, 2, and 3, A designates the furnace of thegenerator, in which are the grate a and the usual tire and ash-pitdoors, b and c.

B designates the bridge-wall, and O theconibastion-chamber, into whichthe gaseous products of the fuel and the air pass over the bridge-wall.

D designates an upper drum for steam and water, arranged in the upperpart ot'the generator, and supported at each end in the brick settingot' the generator, and also by kneepieces or lugs c' on its sides, whichrest upon the brick-work, as seen in Fig. 3. The drum D is designed tohe at all times partly filled with water, and D designates a pipethrough which steam may be taken therefrom for use. The said drum may beprovided with a manhole at each end to enable it to be entered forrepair, if necessary.

In the lower part of the combustion-chamber O, considerably below thedrum D and parallel therewith, is a lower wpter and sediment or muddrum, E, which is shown as smaller than the drum D, and has connected toits ends pipes d d', one of which may serve as a feed-pipe, while theother serves as a blow-0E pipe.

F designates water-tubes, of which any number may be employed to givethe power ot` boiler or generator required. These tubes are arranged inan upright position between the drums D and E, and they are connected attheir upperends with the drum D and at their lower ends with themnd-drum E.

The water-tubes F are made tapering from their upper ends downward, asclearly shown, and the area ot' communication between the tube and thedrum is equal to the area ot' the large upper end ofthe tube, and hencesteam generated at the internal surface ot' the tube has freeopportunity ot' passage upward into the drum D, and through the waterthence into the steam-space, without being opposed in its passage by thedownward current of water which takes place in the center ofthe tubes.

In order to cause the heated gases and products ot' combustion passingthrough the combustion-chamber C to act more effectively upon the tubes,we arrange the tubes in staggered relation to each other, as best seenin Fig. 2- that is, the tubes are placed in three rows or lineslongitudinally ot' the drums, and the tubes in the middle row or lineare placed midway or opposite the spaces between the tubes in the sideor outer rows or lines. This arrangement causes the gases and productsot' combustion to take a zigzag course in passing from front to rear ofthe combustion-chamber O, and to impinge more directly against thesurfaces of the tubes.

In each tube F, near the connection with the mud-drum E, is aange-joint, c, which is secured by means of bolts, and by breaking these`joints the mud-drum E may be removed in case of necessityvior repairs.By placing blank flanges over all the open ends ot' the tubes at thesaid tlangedjoints, the generator may be used even without the mud-drum,if

provision is made for feeding water into one of the tubes or into thedrum D.

In the rear wall of the generator is an opening, Gf, closed by a door,C2, through which access may be had to the combustion-chamber C, andthrough which the drum E may be readily removed, if necessary.

Ve will now describe the fines for the passage of the products ofcombustion from the furnace and combustion-chamber, and for the supplyof air to support combustion.

From the furnace A the smoke and partlyeonsnmed gases, together withair, pass over the bridge-wall B into the combustion-chamber G, whereinthe combustion is completed, and the products of combustion, aftercirculating through the combustion-chamber C and among the tubes F,nally escape through side openings,f, into fiuesf, which extend upwardupon theopposite sides ofthecombustionchamber, and may extend the wholelength thereof. From the lues j" lthe products of combustion passthrough openingsf2 into an escape-flue, G, which extends along the topof the drum, and from which they pass to the chimney under control of adamper, G. (Shown in Fig. 3.) rlhe passage ofthe waste products ofcombustion through the luesf upon the sides of the combustion-chamber Cprevents the radiation ofeiectiveheat outward from the. highly-heatedproducts of combustion in the combustionchamber.

In the front wall of thc furnace A is an airchamber, g, from which airmay enter the furnaces above the grate through numerous perforatious orholes which widely distribute it, and in the bridge-wall B is a similarair-chamber, h h, from which air may be discharged into thecombustion-chamber C through numerous holes or pert'orations, as bestshown in Fig. l. Cold air is taken in at an opening, i, in the back ofthe generator, and thence passes upward through a passage,j, to a flue,H, extending along the top of the generator, from rear to the frontthereof. The Iiue II passes in close proximity to the tlue G, and inthis instance is immediately above the same, and is separated therefromby a thin sheet-metal plate, so that the air passing through the tlue IIis considerably raised in temperature by heat radiated from the heatedproducts of combustion passing through the liuc G, and when it reachesthe front end of the generator is heated to such a degree that it willpromote economical combustion if admitted to the furnace. From the frontend of' the ue II the heated air is admitted by a passage, 7c, to theair-chamber g in the front wall of the generator-furnace A, and aportion of the air passes through the holes or perforations in the saidchamber, while the remainder passes through ues g upon the sides of thefurnace, as seen in dotted outline in Final, and thence to the chamber hiu the bridge-wall, whence it issues from the perforations or holes insaid chamber into the combustion-chamber C. By this arrangement of'air-fines the air to support combustion is highly heated without eXtraexpense, as the heat which is imparted to it would otherwise be wasted.

Of course, in starting the fires air may be admitted to the furnaceentirely below the grate through the ash-pit door, and as much as may benecessary may be there admitted at all times during the working oftheboiler.

In Fig. 4 we have represented a modified form ot' the generator, theconstruction of the several parts of which is like that previouslydescribed. In this case we have represented several of the upper drums,D, and a corrosponding number ot' lower drums, E, extending acrossthefurnace A and combustion-chamber C, and between the steam and waterdrums and their corresponding mud-drums are the down wardly-taperingwater-tubes F. The several drums D are connected by branch pipes Zwith acommon steam-pipe, I, from which steam may be taken for use. In thefront of the furnace and in the bridge-wall B are the air-chambers g and7l, and the arrangement of the air-fines and theireonnecting passagesand the escape-due G and its communicating-passages is the same as thatpreviously described.

What we claim as our invention, and desire to secure by Letters Iatent,is-

The combination of the furnace A and combustiouchamber C, the two heatedair-chambers g h, connected by the side tiues, g', the iiuesf upon thesides ot' the combustion-chamber, and the smoke and air tlues Gr H,extending along the top ot' the generator in close proximity,substantially as specified.

DANIEL KELLY. IILLIAM II. HOFFMAN.

Witnesses FREDK. HAYNns, ED GLA TZMAYER.

